Process of bleaching



CANON F TEXTILES & FiBEfiS,

Patented May 20, 1930 li we GUSTAV BAUM, OF WEISSENSTEIN-ON-THE-DRAU,AUSTRIA, ASSIGNOR TO THE NIAG- ARA ELEOTRO CHEMICAL OOMPANY, INC, OF NEWYORK, N. Y., A CORPORATION PROCESS OF BLEAOHING No Drawing. Applicationfiled July 9, 1928, Serial No. 291,47 l, and in Austria June 30, 1927.

It has previously been proposed to bleach feathers, skins, furs, hair,bristles etc., by placing them in a weakly alkaline bath containinghydrogen peroxide. However, in this process the materials have been moreor less damaged by the bath because of the length of immersion necessaryto complete the bleach.

I have now found that these materials and other delicate animal andvegetable fibres can be bleached with no damage to the goods if they aretreated with hydrogen peroxide i n raggei e reatment of such goods withhydrogen peroxide vapor bleaches the hair and fibres much moresatisfactorily especially in the case of soft furs, than when they areplaced in a liquid bleach bath. This treatment causes no gumminess inthe hair and the bleaching is especially uniform. Bleaching with gaseousperoxide has the further especial advantage of using very smallquantities of hydrogen peroxide. In order to avoid deleterious action onleather when furs are bleached, it is advisable to protect the leatherbefore treatment by coating or pretreatment with fatty materials.

The goods to be bleached are placed in a closed room in which is an openvessel containing hydrogen peroxide solution of suitable strength. Thissolution may be 80% hydrogen peroxide and should be quite stable; thisstability may be secured by addition agents of various kinds. Preferablythe hydrogen peroxide solution is placed in wide shallow pans so locatedthat no particles of hair or fibre or other foreign material which mightcause a decomposition of the peroxide can drop into the vessel. Theclosed room can now be heated in any suitable manner so that thesolution evaporates slowly. The vapors coming in contact with thematerial to be bleached will give a complete and uniform bleachingaction.

EwampZe.-Furs were first lightly brushed on the skin side with asuitable fat and then so hung in the bleaching chamber that they did nottouch each other. A wide shallow pan containing 30% hydrogen peroxidesolution Was placed in the chamber so located and protected that noforeign particles could fall into it. The chamber was closed and heatedby steam or hot air to a suitable temperature, e. g. 50 C. Ventilationwas very slight so as to avoid unnecessary peroxide loss. Considerablebleaching took place in 8 hours. Bleaching by this method is usuallywholly complete in 30 10 hours.

The concentration of the peroxide remaining in the evaporating pancontinuously increases giving an increased bleaching action if thetreatment continues.

The peroxide solution at the start of the bleaching process should beone which can be concentrated to 70-75% hydrogen peroxide without undueloss. T o prevent too high an increase in concentration water may beadded from time to time after the bleaching action continues, e. g. whenabout one half the liquid has evaporated. lVhen the bleaching iscomplete the furs are removed and dried, e. g. at 40 C.

Claims:

1. Process of bleaching which comprises subjecting the material to bebleached to the action of gaseous hydrogen peroxide.

2. Process of bleaching which comprises subjecting the material to bebleached to the action of hydrogen peroxide vapors at a temperature of50 C.

3. Process of bleaching which comprises subjecting the material to bebleached to the action of vapors from a 30% hydrogen peroxide solutionat a temperature of 50 C.

4. Process of bleaching delicate animal fibres which comprisessubjecting them to the action of gaseous hydrogen peroxide.

r 5. Process of bleaching furs, hides, and

pelts which comprises protecting the leather with a suitable fattymaterial and then subjecting the material to be bleached to the actionof gaseous hydrogen peroxide.

6. Process of bleaching furs, hides and pelts which comprises projectingthe leather with a suitable fatty material and then subjecting thematerial to be bleached to the action of gaseous hydrogen peroxide atabout 50 C.

7 Process of bleaching furs, hides and pelts which comprises protectingthe leather with a suitable dressing and then subjecting the material tobe bleached to the Vapors of a 30% hydrogen peroxide solution at atemperature of 50 C.

Signed at Vienna, Austria, June 25, 1928.

GUSTAV BAUM.

